Increasing autoignition temperature of cs2

ABSTRACT

A COMPOSITION OF MATTER SUITABLE FOR CLEANING OIL AND GAS WELLS AND FOR SULFIDING A HYDROTREATING CATALYST WHICH COMPRISES CARBON DISULFIDE CONTAINING 5-40 LV. PERCENT, PREFERABLY 10-30,, OF A REFINERY STREAM BOILING BELOW 250*F., CHOSEN FROM THE GROUP CONSISTING OF CATALYTICALLY CRACKED NAPHTHA AND COKER NAPHTHA.

United States Patent 3,644,433 INCREASING AUTOgGNI'gION TEMPERATURE F C 2 John A. Bichard, Point Edward, Ontario, and Jackson Eng, Sarnia, Ontario, Canada, assignors t0 Esso Research and Engineering Company No Drawing. Filed Mar. 20, 1970, Ser. No. 21,489

Int. Cl. C23g 5/04 US. Cl. 252-364 2 Claims ABSTRACT OF THE DISCLOSURE A composition of mattersuitable for cleaning oil and gas wells and for sulfiding a hydrotreating catalyst which comprises carbon disulfide containing 5-40 lv. percent, preferably -30%, of a refinery stream boiling below 250; F.,.chosen from the groupconsisting of catalytically cracked naphtha and coker naphtha.

BACKGROUND OF THE INVENTION This invention relates to a carbon disulfide composition having increased autoignition temperature.

In the petroleum industry, carbon disulfide is used for sulfiding hydrotreating catalysts, or as a solvent for dewaxing and. sulfur removal at the wellbores of oil and gas wells to'increase flow. Because of its low autoignition temperature of 240 F. carbon disulfide is hazardous and there is reluctance to store and handle this material. Thus a cheap, relatively available agent which would raise its autoignition temperature would permit more effective and safer use of carbon disulfide.

It has already been shown in US. Pat. 3,375,192, issued Mar. 26, 1968 to Rowlinson of Canadian Industries Ltd., that the autoignition temperature of CS can be increased by the addition of 8 to 16% by volume of n-pentane. Petroleum naphtha and chlorinated hydrocarbons are shown to be substantially less effective in increasing the autoignition temperature of CS These data on n-pentane have been confirmed and extended to other parafiins and naphthenes. However such compounds are expensive; On the other hand refinery available.

SUMMARY OF THE INVENTION It has now -been surprisingly discovered that 5 to 40 liquid volume percent of catalytically cracked and coker naphthas boiling below 250 F. when added to carbon disulfide results in a large increase in the autoignition temperature of the carbon disulfide.

Thus the novel composition of this invention comprises a mixture of carbon disulfide and 5 to 40 iv. percent (prefstreams would be cheap and easily I,

erably 10-30%) of a refinery stream boiling below 250 F., chosen from the group consisting of catalytically cracked naphtha and coker naphtha.

The carbon disulfide naphtha mixtures of the above type have an ignition temperature between 490 F. for 10 IV. percent of catalytically cracked naphtha boiling 170- 250 F. and 700 F. for 30 IV. percent of catalytically cracked naphtha. The comparable autoignition temperature range for coker naphtha boiling 160-190 F. lies between 495 F. and 660 F. For comparison, autoignition temperature of carbon disulfide alone is 240 F.

These compositions possess satisfactory solvent power for waxes and sulfur found in oil and gas wells and are also suitable for sulfiding catalysts.

When used as well solvent the novel composition of this invention is pumped down the well and allowed to remain until the wax and sulfur has been dissolved after which it is removed from the well.

When used to presulfide a hydrotreating catalyst the composition is passed over the catalyst, generally, in the presence of hydorgen at a temperature in the neighborhood of the subsequent reaction temperature until the catalyst is fully sulfided, after which the flow of composition is stopped.

DETAILED DESCRIPTION A synergistic effect occurs when the autoignition temperature of admixtures of an added component with carbon disulfide is higher than either the carbon disulfide or added component alone. The present studies confirm that n-pentane at concentrations of 10 and 30 liquid volume percent (lv. percent) increases the autoignition temperature of CS Several other normal and isoparafiins and naphthenes also resulted in a synergistic autoignition effeet: However, an aromatic, such as benzene, added at 10 and 30 lv. percent concentration, did not raise the autoignition temperature. Toluene and xylene were only slightly more efiective than benzene.

The following. example shows that catalytically cracked and coker naphthasboiling below 250 F. gave the largest increase in autoignition temperature of carbon disulfide. This is unexpected since these light cracked naphthas contain aromatics. A comparison with other compounds including check runs on n-pentane and straight-run petroleum naphtha; is included. The flammability studies were made in accordance with ASTM procedure D-287- 55.

EXAMPLE 1 A series of solutions was made consisting of carbon disulfide in admixture with various hydrocarbons and refinery streams having the following inspections.

' INSPECTIONS ON REFINERY STREAMS USED IN AUTOIGNITION STUDIES Naphtha Gas oil Virgin Udex (rainrafli- Steam Turbo run Cat Steam Type bow) nate cracked cracked Coker Fuel light cracked cracked Ooker Gravity, AII 74. 73. 2 57. 5 29. 8 64. 5 47. 2 32. 2 22. 0 13. 4 33. 2 Distillation, ASTM IBP 108 136 108 204 92 285 516 394 376 320 5% 127 148 128 216 124 309 544 438 418 381 107 130 152 136 221 134 317 560 454 423 413 137 156 149 238 148 327 572 474 431 467 141 0 164 247 159 335 580 488 437 505 146 164 185 258 168 343 586 501 442 534 152 169 208 272 177 351 592 517 446 556 157 175 234 290 186 360 597 534 452 574 163 184 260 309 196 370 606 550 460 594 170 197 293 333 209 384 616 572 473 613 180 222 323 355 227 401 632 601 490 645 188 260 344 370 239 415 650 629 509 674 FBP 229 320 390 385 287 456 654 640 549 678 Bromine Number 0. 1 4. 5 99. 2 69. 5 150. 2 0 5 5.0 19. 4 37. 8 25. 6 FIA, 1v. percent:

Saturates 95 90 22 7 19 82 61 26 8 Olefins 0 0 24 93 73 0 0 9 92 Aromatics 5 10 24 8 18 39 65 Isopentane LV percent 4 1 l 5. 7 0 2 0. 3 0 0 0' 0 0 n-Pcntane LV percent- 8 4. 5 1 0. 6 0.1 2 1.4 0 0 0 0 0 Total pentanes, LV percent. 12 5. 5 6.3 0. 1 1. 7 0 0 0 0 0 (Oi-170 F.Pentanes LV percent-l9.0. 170-250 F.Pentanes LV percent 0.0. n- F.-Pentancs LV percent 5.1. ISO-190 F.--Pentancs LV percent-0.0.

The following data were obtained.

AUTOIGNITION TEMPERATURE OF CARBON DISUL- PHIDE AND HYDROCARBON MIXTURES Hydrocarbon added to CS2, LV

percent Autoignition temperature, F.

35 Pure hydrocarbons:

n-Pentane 240 515 720 485 240 525 725 650 240 485 650 530 n-Hexane 240 400 640 430 Methylcyclopentane- 1- 240 455 615 495 Cyclohexane 240 405 580 495 40 240 220 225 1,040 240 p 255 355 955 Xylene 240 265 375 955 Refinery streams:

Naphthas:

Virgin 240 415 645 475 Rafiinate 240 395 510 460 Catalyst cracked 240 490 700 505 45 Catalyst cracked fraction.

The above data clearly show that besides normal pentane, other pure hydrocarbon, e.g; isopentane, pentene-l,

normal hexane, methylcyclopentane and cyclohexane all 60 that catalytically cracked naphtha and coker' naphthas 65 boiling below 250 F. increase the autoignition temperature of CS despite their aromatic content; A synergistic elfect is noted at 30 1v. percent. This effect is not due to the presence of pentane since the amount of pentane in the CS containing 301v. percent catalytically cracked naphtha, for example, was 2.1% At this pentane concentration, the autoignition temperature of CS is only raised to 250 F, while the CS -30 lv. percent mixture of catalytically cracked naphtha had an autoignition temperature of 700 F. indicating that other components of the naphtha have a very beneficial and unexpected effect in raising the autoignition temperature of CS I No important increase is noted with benzene and only a small increase with toluene and xylene. Virgin naphtha and raflinate from Udex extraction and steam cracked naphtha, or any of the gas oils show significantly smaller increase in autoignition temperature than catalytically cracked and coker naphtha boiling below 25 0 F.

The nature and advantages of the present invention having thus been fully set forth and specific examples of the same given, what is claimed as new, useful and unobvious 1s: 1

1. A composition of matter consisting essentially of carbon disulfied containing 5-40 liquid volume percent of a refinery stream boiling below 250 F. selected from the group consisting of catalytically cracked naph ha. and coker naphtha. l 1

2. The composition of claim 1 in which the carbon disulfide contains 10-30 liquiclvolume percent of the refinery stream.

References Cited v i STATES PATENTS Wiewiorowski et al. 252 364 HERBERT B. GUINN, Primary Examiner US. Cl. X.R. 

